Clement littlefield



C. LITTLEFIELD.

MEASURING LUMBER.

No. 80,077. Patented July 21, 1868.

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Letters Patent No. 80,077, dated July 21, 1868 INSTRUMENT ronmnasnaineLUMBER.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, CLEMENT LITTLEFIELD, of Kennebunk, in the county ofYork, and .State ofdliaiue, hai/e invented a new and useful Machine forGiving the Cubical Contents of Round or Square Timber, Wood, Bark,- orStone, which I call Littlefield's Ready Reckoner and Cubical Calculator,and I do hereby declare that the following is a full and exactdescription of the same, reference being had to the annexed drawings,making a part of this specification, in which Figure 1 is a plan view ofmy device, and v I Figure 2 is a sectional view thereof at the pointindicated by the red line 5/ y. cn fig. 1.

This invention consists of an outer circle or disk, A, and an innercircle, B, of which the outer is movable, or made to revolve around theinner to any desired point by holding the handle attached to the innercircle; and moving the outer with the hand. I i

C C C are screws, securing the inner circle to a bar,- D, on theunderside of the device, which bar projects sulficicntly from theperiphery of the outer circle to form a handle.

The heavy circular line E indicates the line of union of the outer andinner circular plates, by means of a shoulder sunk on the periphery ofthe inner plate, as shown by letters F R Both plates, on their frontsurfaces, are divided into feet and inches by lines marked across; theinner circle having a radius largerthan the outer.

To compute the contents of a piece of timber, find the lengthasexpressed in feet upon the outside circle; place the same over thefigure 1:2 upon the inside circle; then, directly above the squareof-the stick upon the inside, will be found the cubical contentsdesired.

To get the cubic feet of square or round timber, the length is on theouter circle, the diameter is on the inner circle, the contents on theouter.

( Examples. 7

Suppose a stick of timber to be twenty feet long, and eighteen inchessquare; required, tl1e-numbcr of cubicfeet contained. i 7

Place the figure 20 on the outer circle over the figure 12 on the innercircle; find figure 18 on the inner circle, and opposite will be 45cubic feet, the answer.

For round timber, stick twcnty-five feet long, twenty inches indiameter. In Maine, sixteen inches diameter of sound timber isconsidered equal to twelve inches square; therefore, place the figure 25on upper circle over 16 inches on the inner; then find the figure 20 onthe inner circle, and opposite is 39 feet, the contents.

For unequal-sided timber, stick thirty feet long, fourteen by twentyinches. To get the mean proportion, place the figure 30 on the outercircle opposite figure 20 on the inner, then find 14 on the outer, andopposite will be 162-, the mean proportion; then place 30 over 12, asfor square timber, and find 16g} on the inner, and opposite B58 fect,the answer.

For scaling round logs for board-measurmstick eighteen feet long, andseventeen inches diameter; required, the number of feet of boards. Place18 inches in the outer circle over 19 inches in the inner, then findfigure 17 on the inner, and opposite will be 229 feet, the quantity ofboards in the log.

To find how large a square can be hewn from a round stick, stick thirtyinches in diameter, place the figure 30 on inner circle under figure 24on the outer, then find figure lid on the outer circle, and oppositewill be 21} inches, what the stick will square. I

Wood, bark, and stone can be measured in the same manner.

The principle by which I arrange the figures upon the tables is calledthe logarithm of numbers, and of which I make no claim, for it has beenknown for my years.

My device consists in adapting logarithms to a circular movable form,and thereby renderingit practical, convenient, and correct.

I will first explain the manner of arranging the figures on a straightline, as by that means my device will be more readily understood.

The first point to be settled is, how far shall the calculations becarried. un the drawings, in this case, I o as far as .256, which issuflicient for the measurement of timber, stone, and the like.

Inthis case, I take thirty-seconds of an inch for my divisions. Now, thelogarithm of 256 is 2408.24. This,'divided by 32, gives 75 therefore thescale should be 75 inches in length.

I will now commence to mark on the scale. 1 is at the end. The logarithmof 2 is 301.03. Now, the dis tnnce on .the scale from 1 to 2' must be301.03 thirty-seconds of an inch, which will be Take this distance inthe dividers, and measure from the end, and it will give the place onthe scale for 2; then the samefrom 2 to 4, from 4 to 8, 8 to 16, 16 to32, 32 to G4, 64 to 128, and 128 to 256. This gives the above numbersand their places upon the scale, thus: 2, 4, 8, 16, 32, 64, 128, 256

New, I will find the place for 3. Thelogarithm of 3 is 477.12; this is14-inches; so I commence that distance from the end. I' then take theabove distances from 1 to 2, and this will give the place for 6, then12, 24, as, 96, 12s, and 192. v

T find the place for 5, I take its logarithm, which is698.97, making21%} inches from the end.- Then take the same distances as from 1 to 2and this will be the place for 10, 20, 40, 80, 160, 8ic. I proceed inthis way until-all the numbers are upon the board or scale. Thisexplains the outer circle shown on the drawings.

The figures upon'the inner circle are obtained upon the same principleas the foregoing, except that the divisions are just double thedistance, (say, from 1 to 2 is 602.06,) and will form a line of squaresand roots with the outer circle thus:

Upper or outer lineorcitclc i, 4, 9, 1o, 25, so, 49, 64, 81, 100, 121,144, 169, 196, 225, 256.

Lower or inner line or circle, 1,2, 3, 4, 5, .6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16. This is divided, so as to give cubical measure. t

To apoly the foregoing to a circular form, I construct a wheel sixteenfeet in diameter, and then make the divisions on a thin straight batten.I then bend this batten around the periphery of the wheel. This forms anarm of eight feet from the centre of the wheel. I make the wheel thuslarge, to give such a radius as to enable me to make themeasurements'anddivisions correct as I come towards the centre. This could not bewell done on a. small wheel, as the divisions would necessarily be toominute.

What I claim as my invention, and desire to secure by- Letters Patent,is-- The application of-logarithms to a circular movable form, with adouble radius mathematically divided, so

that one part works in conjunction with the other. substantially as' andfor the purposes specified.

GLEMENT LITTLEFIELD. Witnesses:

M. C. Tnomrson, S. E. BRYANT.

